So complicated! Those issues could easily be hardware bugs.
If the author is here - excellent writing, very easy to follow even if (like me) a person is a noob at low level stuff:)
Thank you for reading :-)
Those Bouffalo Lab chips are self-destructing, there's no write protect for the EFuse bits, one wrong register write and the chip's locked in secure boot mode and thus dead. Go for Beken instead, they designed the EFuse controller sensibly - and are based on the same CEVA RivieraWaves IP.
That's a feature, depending on your application. If you (intentionally) blow the secure boot fuses, you want it to _stay_ in secure boot mode.
But there should be a way to lock those fuses before shipping the product to market. Otherwise the device can be permanently bricked and the hardware will need to be replaced. On Espressif and Beken chips these fuses are lockable. Once locked, they can never be written to again.
My first encounter with UART was when I was trying to write a simple kernel thing for Qemu ARM64 virt machine. Not understanding UART buffer I ran into a lot of infinite print loops and funny moments. I wish I had a document like this back then, good stuff.
This person is building out a whole detailed series on this Ox64 board. Great stuff.